Asset condition monitoring in an electric motor

• US 8,981,697 B2
• Filed: 10/04/2012
• Issued: 03/17/2015
• Est. Priority Date: 10/07/2011
• Status: Active Grant

• Current Assignee: Schweitzer Engineering Laboratories, Incorporated
• Original Assignee: Schweitzer Engineering Laboratories, Incorporated
• Inventors: Zeller, Mark L.
• Primary Examiner(s): Ip, Paul
• Application Number:
  US13/645,361
• Publication Number:
  US 20130088799A1
• Time in Patent Office: 894 Days
• Field of Search: 318/430, 318/432, 318/400.02, 318/494, 318/778, 318/400.34, 318/802, 318/702, 318/798, 318/807, 318/453, 318/490, 361/24, 361/32
• US Class Current: 318/432
• CPC Class Codes: H02H 3/083 for three-phase systems
• CPC Class Codes: H02H 3/093 with timing means in general H02H3/027; thermal delay H02H3/085; timing means for undervoltage protection H02H3/247
• CPC Class Codes: H02H 3/10 additionally responsive to some other abnormal electrical conditions
• CPC Class Codes: H02H 3/165 for three-phase systems
• CPC Class Codes: H02H 3/207 also responsive to under-voltage window comparators for indication G01R19/165
• CPC Class Codes: H02H 3/34 of a three-phase system
• CPC Class Codes: H02H 3/385 using at least one homopolar quantity
• CPC Class Codes: H02H 5/042 using temperature dependent resistors
• CPC Class Codes: H02H 7/0816 concerning the starting sequence, e.g. limiting the number of starts per time unit, monitoring speed during starting
• CPC Class Codes: H02H 7/0822 Integrated protection, motor control centres

Abstract

The motor monitoring system of the present disclosure uses several calculated monitoring values to determine a status of a motor and take a predetermined action when a threshold corresponding with the monitoring value is exceeded. The threshold may be calculated by an intelligent electronic device (IED) monitoring the motor. The predetermined action may include further monitoring of the motor. The predetermined action may include monitoring equipment not directly monitored by the IED.

Claims

1. An intelligent electronic device (IED) for monitoring and protecting an electric motor, comprising:

a plurality of electrical signal inputs for obtaining a plurality of electrical signals representing operating parameters of the electric motor;

a monitoring module configured to;

receive the electrical signals representing operating parameters of the electric motor;

calculate a monitoring value from one or more of the electrical signals of the plurality of electrical signals during a plurality of successful operations of the electric motor;

calculate a threshold monitoring value from the monitoring value;

receive new electrical signals representing operating parameters of the electric motor;

calculate a new monitoring value from the new electrical signals; and

initiate a defined action when the new monitoring value deviates from the threshold.

2. The IED of claim 1, wherein the defined action comprises initiating a monitoring process within the IED.

3. The IED of claim 1, wherein the defined action comprises tripping a breaker to disconnect the motor.

4. The IED of claim 1, wherein the defined action comprises triggering an alarm.

5. The IED of claim 1, wherein the defined action comprises initiating a monitoring process for equipment other than the motor.

6. The IED of claim 1, wherein the monitoring module is further configured to initiate a defined action when the monitoring value exceeds the threshold.

7. The IED of claim 1, wherein the IED further comprises a temperature input for obtaining a temperature signal from the electric motor, and the monitoring module is further configured to calculate a monitoring value from the electrical signals and the temperature signal.

8. The IED of claim 1, wherein the operating parameters include one or more of:

a motor bearing temperature;

a motor winding temperature;

ambient temperature of a motor;

a neutral current;

a phase current; and

a phase voltage.

9. The IED of claim 1, wherein the monitoring value is selected from the group consisting of:

a temperature at a point of the motor;

neutral current;

phase current;

phase voltage;

thermal capacity used during a start;

motor start time;

starts since last reset;

phase current imbalance;

negative-sequence current;

time to trip;

phase-to-phase voltage;

impedance during start; and

, starts per time.

10. A system for monitoring assets in an industrial or utility operation, comprising:

an electric motor;

an intelligent electronic device (IED) in communication with the electric motor, and configured to;

receive electrical signals representing operating parameters of the electric motor

calculate a monitoring value from the electrical signals during a plurality of successful operations of the electric motor;

calculate a threshold monitoring value from the monitoring value

receive new electrical signals representing operating parameters of the electric motor;

calculate a new monitoring value from the new electrical signals; and

initiate a defined action when the new monitoring value deviates from the threshold.

11. The system of claim 10, wherein the defined action comprises initiating a monitoring process for another piece of equipment in the industrial or utility operation.

12. The system of claim 10, wherein the defined action comprises initiating a monitoring process within the IED.

13. The system of claim 10, wherein the defined action comprises tripping a breaker to disconnect the electric motor.

14. The system of claim 10, wherein the defined action comprises triggering an alarm.

15. The system of claim 10, wherein the IED is further configured to initiate a defined action when the monitoring value exceeds the threshold.

16. The system of claim 10, wherein the IED is further configured to receive electrical temperature signals representing an operating parameter of the electric motor, and calculate a monitoring value from the electrical signals and the temperature signals.

17. The system of claim 10, wherein the operating parameters include one or more of:

a motor bearing temperature;

a motor winding temperature;

ambient temperature of a motor;

a neutral current;

a phase current; and

a phase voltage.

18. The system of claim 10, wherein the monitoring value is selected from the group consisting of:

a temperature at a point of the motor;

neutral current;

phase current;

phase voltage;

thermal capacity used during a start;

motor start time;

starts since last reset;

phase current imbalance;

negative-sequence current;

time to trip;

phase-to-phase voltage;

impedance during start; and

, starts per time.

19. A method comprising:

receiving at an intelligent electronic device (IED) a plurality of electrical signals representing operating parameters of an electric motor;

calculating a monitoring value based on one or more electrical signals of the plurality of electrical signals during a plurality of successful operations of the electric motor;

calculating a threshold monitoring value from the monitoring value;

receive new electrical signals representing operating parameters of the electric motor;

calculate a new monitoring value from the new electrical signals; and

initiating a defined action when the new monitoring value deviates from the threshold.

20. The method of claim 19, wherein the defined action comprises initiating a monitoring process for another piece of equipment in the industrial or utility operation.

21. The method of claim 19, wherein the defined action comprises initiating a monitoring process within the IED.

22. The method of claim 19, wherein the defined action comprises tripping a breaker to disconnect the electric motor.

23. The method of claim 19, wherein the defined action comprises triggering an alarm.

24. The method of claim 19, wherein the IED is further configured to initiate a defined action when the monitoring value exceeds the threshold.

25. The method of claim 19, wherein the operating parameters include one or more of:

a motor bearing temperature;

a motor winding temperature;

ambient temperature of a motor;

a neutral current;

a phase current; and

a phase voltage.

26. The method of claim 19, wherein the monitoring value is selected from the group consisting of:

a temperature at a point of the motor;

neutral current;

phase current;

phase voltage;

thermal capacity used during a start;

motor start time;

starts since last reset;

phase current imbalance;

negative-sequence current;

time to trip;

phase-to-phase voltage;

impedance during start; and

, starts per time.